Life raft



June 23, 1942.; E. 'r. FLYNN 2,287,513

LIFE RAFT v Filed Oct. 6, 3,941 3 Shee ts-Sheet 1' if a it 11 III fife/"224a Q June 23', 1942.? EQT. FLYNN 2,237,513

LIFE RAFT I File l Oct. 6, 1941 i '3 Sheets-Sheet 5 INVENTOR.

BY fliiarizqy Patented June 23, 1942 LIFE RAFT Edmund T. Flynn, Scituate, Mass, assignor to William J. Sullivan, Boston, Mass, and Frank A. Powers, Quincy, Mass.

Application October 6, 1941, Serial No. 413,725

16 Claims This invention relates to improvements in life rafts.

More particularly it provides improvements in a buoyancy unit or float for such rafts, on which any suitable platform may be suspended or otherwise mounted.

It is among the objects of the invention to provide a float which may be made entirely of wood of varieties which are available in quantity at low cost as compared with comparable prior constructions which employ diflicultly obtainable and expensive basswood or balsa for buoyancy, or which combine the balsa with sheet metal tubing, the metal for which is now inaccessible in quantity because of government priorities for defense purposes.

Another object is to employ an endlesstubular construction having extent in the form of an oval, and having cross-partitions dividing the interior of the tube into a multiplicity of air chambers, whereby puncture of the tube wall at any particular chamber has no effect on the chambers whose walls remain intact.

A further object is to provide a wooden frame structure which, without anycovering layer of wood or metal, may present a substantially smooth exterior surface over which the usual exterior covering of canvas or the like may be secured directly.

Still another feature resides in a structural frame having a series of ribs which are disposed around a torsional tube which may extend at the axis of the larger tube, and which itself is divided into a multiplicity of air chambers occurring in succession around the oval of the float.

Another feature is that pre-formed plywood may be applied over the structural frame, to provide a substantially waterproof covering, and to lend strength and durability to the float, the usual exterior covering of canvas being applied over the plywood.

It is, moreover, an important feature that my improved float is reversible the same as prior floats, and is adapted for any suitable platform to be suspended thereon according to well known procedures.

The mentioned objects and results may be attained with a structural frame made entirely of wood, in the general shape of an oval, and having ribs extending endlessly along the oval contour of the float, in spaced relation around the axis of the sides and ends of the oval. Cross partitions are spaced apart along the extent of the oval frame, supporting the said ribs and maintaining their said spaced relation.

In a preferred form, pre-formed plywood covers the frame throughout the oval extent thereof, beingglued thereto in suitable sections to provide a tubular oval float, whose sides and ends are circular in cross-section, and have a succession of air chambers such that puncture of the wall of any particular chamber leaves the buoyant character of all other chambers unaffected.

Any usual exterior covering, of canvas or the like, may be applied over the plywood; and any suitable platform may be suspended from the float by rigging well known in the art.

If desired, the plywood covering for the frame may be omitted, and the spaces between ribs in the region at the circumference of the crosssectional circle of the frame be filled with any suitable wood filler or other buoyant material, to provide an approximately smooth exterior of frame for reception of the exterior layer of canvas thereon directly.

Also, for additional strength and durability, and for increased safety against loss of buoyancy, a torsional tube of plywood, of rectangular cross-section, may extend at the axis all around the oval, with interruption of continuity of the air space within the tube at each said cross-partition of the frame.

It is intended that the patent shall cover, by suitable expression in the appended claims, whatever features of patentable novelty exist in the invention disclosed.

In the accomyanying drawings:

Figure 1 is a top plan of a life raft embodying features of my invention, a portion being broken away to show the interior frame structure;

Figure 2 is a side elevation thereof;

Figure 3 is an elevation in section on 3--3 of Figure 1, 'on an enlarged scale;

Figure 4 is an elevation in section on 4-4 of Figure 3;

Figure 5 is a View similar to Figure 3, but on smaller scale, showing a modifiedform in which the canvas covering is applied directly to the frame, the spaces between ribs, at the circumference of the frame being filled to provide an approximately smooth exterior frame surface; and showing also cross-partitions of plywood;

Figure 6 is an elevation, on the same scale. as Figure 5, of a section of my improved frame, stripped of all covering; and

Figure 7 is a perspective of a plywood cross partition having a central element on each face for seating the end of a torsion tube section.

Referring to the drawings, the buoyancy unit or float It] may have the oval shape represented in Figure 1, its sides and ends bei'ng preferably circular in cross-section,

Such floats ordinarily. have an exterior covering of canvas or the like suitably treated for waterproofness, or combined with a waterproofing substance applied under the canves.

A platform 12, of any desired or usual construction, may be suspended by suitable rigging from the float, such as from a rope l4 held on the float by the canvas straps or bands I6.

The invention has to do primarily with a structural wooden frame for the float which cooperates admirably in providing needed buoyancy coupled with strength, durability and re-' quired characteristics of elasticity which makethe float entirely adequate for withstanding the rigorous and strenuous service: required of; life rafts.

The structural frame comprises a series of endless ribs 18, 20, 22, which extend inrsp aced relation along the sides and around the ends off the oval float. Disks 24 may be suitably spaced are made up of pieces 32 and 36, of which the.

pieces 32, 34- may be of solid wood such as ash,

with glued tongue-and-groove securement to-' gether as indicatedattil in Figure 3. The part 36 maybe of three-ply wel dwood securely gluedwith its edges engaged in; grooves 40 inthe pieces 32, 34;

However, disks made of a suitable number of plies ot weldwood, as indicatedat 24 in Figures 6 and '7, may be employed with satisfactory re--v sults.

The ribs I8; 20, 2 2 may-beef solidwood such.

as ash, whichlendsitself to the required bending of ribsat the end regions of the oval float.

Convenientlyand economically, each endlessrib may be constituted of several sectionsglued to gether. As illustrated; by the oblique lines at 23; in: Figure 6, each glued joinder of rib; sections;preferably involves the: clamping together of: relatively long skived end -portionsofadjoining sections, with glue between, the clamping being conveniently effected by locating each ribjointatanotch-EG, 28 or 30 of a disk, 24',

so that; the'skived end; of ribsections can be forced together between the walls-of the notch, with the notch Walls serving as a clamp. The joinders 23; of; different ribs, however, will; be preferably staggered-along the float,

The rib sections; which are to V have curved;- ex;- tent at end; regions of the floatwill be suitably prepared by steaming or wetting, so that-- they may be bentwhile being applied a, Waterproof glue; being; employed throughout which effectssecure wood to-wood joinders in: spite of moisture which maybeon a surface orsurfaces which are to be glued.

'Ifhe torsion tube 42; (Figures 1, 3 and-D at the region; of the 'axisof the disks 24 and extending all around the oval contour of the float, is re garded as a desirable but not an essential element. As illustrated,it comprises multiple sections 42? of rectangular plywood tubing, each section extending between two of thedisksia In Figures Sand 4 the sections 62* are shown fitted into the rectangular opening 44. formed by the pieces- 32-, 34 of the disk, with itsend butted-against the ply ood piece 36-. which closes the opening 44 and which alSoserves-Jto close. the end of the tube section 42.

In the case of the ply-wooddisks 2,4, I preferto secure centrally OfeaQh-faQe a rectangularpiece 46 (Figure 7) for nicelyfltting-theinterioncrossr. sectionof a tube section42f, so thattheendjof a tube section may befltted over and glued to this piece 46, with the end of the section butted against and secured to the face of disk 24.

In either. case the tube sections 42' will be straight tubes with weldwood walls, such as three plies making a total thickness of walls of one-eighth of an inch, for example. At the curved end regions of the oval float these seccovering, oicanvas- 62,01: the like, whiclimay be tions 42', instead of following the curve of the frame, extend: each in a straight line from the centergof one-disk 24 or 24' to the center of the nextdisk.

In addition to its strength-giving advantages, the torsion tube 42 provides multiple additional airpockets for providing substantial unaffected buoyancy when thewallsof any one or-more-individual air chambers of the float become punctured.

As seen in; Figure, 1, the disks 24. which occur? along theparallel-sidesof thezfloat are arrangedwith their faces parallel to each; other. Atthe rv n h flo tg o r ri he i ks r s ose d all he. ent r.- Q ur r Of he m iq he fiet s n- F ur -L n also} to; some: extent in the largershowing of Figure y; his; q str c i ni bm nesi ifihth escribed: arrangement of the; ribs; maximum Stre t of I rame tieinsdr d a la i ea eewh shw su t n u c r sl mn it normal shape afterrelatively severe distortions. In the form of the, invention illustrated: in

Figures; 1-4; a plywood, sheathing-may entirely cover, the. structural frame. As illustratedthis. covering;- ccmprises; two layers 48-, 50 of three, Pl WQ WQQaQplied in-sections52, 54 (Figure the-shape-it: will-have on the framepeach ex:

tending around onegh alf; thecircular: crossesection. The sections may,be five;or more inchesin width, with thebutteiedges ofadjacent sections-- staggered. in outer. and; inner. layers.

The prer'fonned inner sections.52 aregluedto the ribs}of the gframe and the ends of ,each-innersection may be butted at a rib as at; 56, in Figure with the-j ointstaggered in relation, to the butted joint of an underlying, section.

Sucha .plywoodj co v ering, lendslgreatl, strength to the float as a whole and constitutesinitself an approximately Watertight sheathing for. the float.

However, I I prefer, to apply the usual. exterior suitably treated'to be waterproof, or which may be applied, over. a. layer of reinforced asphalt paper, 64, (Figure, 3),, or otherv waterproofing.

substance.

he; canvas. exte o o in 62 p o ides. a

convenient. means or. mountin he ca vas straps orbands l6 which int-urncan support the p d-fo su p nsion of'a platf m 1 In Eigurebja modified'form of frame structure:

is illustrated; in which; the-spacesbetween ribs i8, 20, 22' are fllleduwithgpre-formed pieces 66' any suitable buoyant material; of'cross-secememb re- Q- fi w d isdi e we n a iac n r b The r outer surfaces may be bufiedror otherwise treated to provide a smooth cylindrical surface on the frame. In this case the exterior canvas covering 62 may be applied directly on the frame, or over asphalted paper as in Figure 3.

Figure shows also how horizontal and vertical plywood partitions 68, It may be combined with the ribs and cross-partitions heretofore described, being preferably pre-formed with the curvatures which they will have in the float. The partitions extend from one cross-partition to the next one, and from side to side of the frame, between opposite ribs, being glued in place, with additional securing means if desired. In addition to the strength-giving character of these partitions, they divide each air chamber between cross-partitions into quarters, thus multiplying the number of individual air chambers in the float by four.

The torsion tube 42 would not be used with the partitioned structure of Figure 5.

I claim as my invention:

1. A buoyancy unit for life rafts, comp-rising an endless structural frame having a multiplicity of cross-partitions arranged in spaced relation along the endless extent of the frame, and a series of endless ribs extending along the frame and spaced apart around the edges of said crosspartitions, each rib being secured to the edge region of each partition; and a waterproof covering of sheet material enveloping the ribs and partitions throughout the endless extent of the frame, and forming, with said cross-partitions, a succession of water-tight air chambers within the frame.

2. A buoyancy unit as in claim 1, wherein the frame has its said endless extent in the general form of an oval, and the said ribs are bent at the curved regions of the oval, and the said partitions, at the curved regions of the oval, are disposed radially with respect to the center of curve at their particular locations.

3. A buoyancy unit as in claim 1, wherein the said cross-partitions are disks with notches in their edges, and the said ribs are spaced around the peripheries of the disks, each rib seated in a notch of each disk.

4. A buoyancy unit as in claim 1, wherein the said cross-partitions and ribs are made entirely of wood, and there is a covering of plywood applied over the ribs and partitions and having a general cross-sectional contour corresponding to the edge contour of a said cross-partition.

5. A buoyancy unit as in claim 1, wherein the said cross-partitions are circular disks of wood, and the said ribs are strips of wood, and there is a covering over the ribs and partitions having cross-sectional circular contour approximating in size the circle of a said disk; said covering comprising associated sections of plywood preformed with curvatures approximating their ultimate curvatures on the frame.

6. A buoyancy unit as in claim 1, wherein a tubular strut extends from center to center of successive ones of said cross-partitions.

'7. A buoyancy unit as in claim 1, wherein a rectangular tube made of plywood extends as a strut from center to center of successive ones of said cross-partitions.

8. A buoyancy unit as in claim 1, wherein each said cross-partition is a circular disk made of wood sections with tongue-and-groove securement together, a central section of the disk being of plywood of less thickness than the surrounding sections, whereby the laterally projecting inner edges of the surrounding sections may constitute a seat for a strut which may extend from one to another of the disks.

9. A buoyancy unit as in claim 1, wherein the said cross-partitions are made entirely of plywood.

10. A buoyancy element as in claim 1 wherein the said cross-partitions are made entirely of plywood, and there is a central projection on each face of the disk for constituting a seat for a strut which may extend from one to another of the disks.

11. A buoyancy unit as in claim 1, wherein there is a horizontal and a vertical partition, each extending between successive cross-partitions and between tworibs on opposite sides of the axis of the cross-partitions.

12. A buoyancy unit as in claim 1, wherein the said cross-partitions are circular disks of wood, and the said ribs, each comprises a series of strips of wood with skived ends of adjacent strips glued together, there being notches in the edges of the disks for reception of the ribs, and each said glued joinder of skived ends of rib strips being at a said groove, with the walls of the groove constituting a clamp.

13. A buoyancy unit as in claim 1, wherein there is a covering over the ribs and partitions made of sections of preformed plywood, the said plywood sections being applied in two layers of which the butted edges of inner and outer sections are staggered.

14. A buoyancy unit as in claim 1, wherein the said cross-partitions are circular disks of wood, and the said ribs are of wood, spaced around the circumference of the disks; and a plywood covering around the ribs and disks made of preformed sheet sections of which each section is pre-formed with curvature for extending around approximately one-half of the circular crosssection as determined by the diameter of said disks.

15. A buoyancy unit as in claim 1, wherein the said cross-partitions are circular disks of wood,

. and the said ribs are of wood, spaced around the circumference of the disks; and a plywood covering around the ribs and disks made of preformed sheet sections of which each section is pre-formed with curvature for extending around approximately one-half of the circular cross-section as determined by the diameter of said disks; and an exterior covering of fabric secured over the plywood; there being a waterproofing material intervening between the plywood and the fabric.

16. A buoyancy unit as in claim 1, wherein the said cross-partitions are circular disks of wood, and the said ribs are of wood; the outermost portions of said ribs being at a distance from an imaginary line passing through the centers of the disks equal to the radius of a said disk; filler material between the said outermost portions of said ribs making the exterior of the frame approximately smooth; and an exterior covering of fabric secured over the frame; there being a waterproofing material intervening between the surface of the frame and the exterior fabric.

EDMUND T. FLYNN. 

